公安机关及其人民警察牢记全心全意为人民服务宗旨的要求是( )。

A．要真正把人民群众当做国家的主人，事事为群众着想，做人民的孺子牛

B．要勤政廉洁，秉公执法；乐于奉献，不怕艰难困苦，不怕流血牺牲

C．关心群众疾苦，开展便民、利民、助民活动，为群众排忧解难

D．自觉接受群众监督，坚决杜绝耍特权、逞威风、摆架子，甚至仗势欺压群众，破坏警民关系等违法乱纪的行为

It is in that primary school ________ Mary once studied for six years that she will build a library，________ delights all the students and teachers in the school.

A．where；that

B．that；that

C．that；which

D．where；which